Toshiba Satellite L300D-243 BIOS Recovery Problem

I've been having a few problems with my Toshiba Laptop over the past couple of days.

The BIOS had become corrupt and would no longer boot, so I used the Insyde BIOS Recovery Process to salvage it and it worked and I thought it was a life saver.

However, when checking the system after it recovered, the BIOS had a problem with it's SLIC Table (Bad SLIC DATA).

So me, in all my wisdom, thought it would be a good idea to downgrade from 1.80-WIN to 1.70-WIN with a view to try and repair it.

Toshiba do not offer previous BIOS version for each laptop, so I found 1.70-WIN by googling for it and came up with this. It's for the Toshiba L300D-11V, the same as mine with a slight variation, mines a L300D-243.

So I automatically assumed it was the correct BIOS, but slightly older. I unchecked the version check in Options in Insyde Flasher and continued to overwrite the newer BIOS with the older one... How wrong I was!

Now I'm trying to recover my BIOS the same way I did before (by putting the BIOS file PSAP180.fd as BIOS.fd onto a Fat 32 formatted USB and holding down FN-F upon start).

The USB flashes once, but gets ignored and the system just sits idol with a Black screen again.

I've used Andy's tool to find the correct name for the BIOS file and both files are used are coming up as "BIOS.f?".

What I am wondering, because the old BIOS version I put on, do I now need to use a different Key Combo to force the update or should it still be the same - IE, that doesn't change - it's a hard-coded command in the Motherboard itself?

I've found the latest BIOS for this system is definitely PSAP180.fd and that trying to use PS10A170.fd is a very stupid move.

Can anything been done to force the Laptop to accept the original BIOS I flashed or have a completely killed it now?

Going back to trying to fix this, this week. I've also since got hold of another L300D that I could also transplant the BIOS chip out of if need be - if I can find it.
If anyone can assist, would be appreciated.

Thanks.

--edit
Can't believe Toshiba have done the dirty and removed all service manuals from t'internet.